Automatic draft and combustion control



Feb, 6 1934-; A v c uyssg 1,946,300

AUTOMATIC DRAFT AND COMBUSTION CONTROL Filed July 6. 1931 2 Sheets-Sheet 1 l |||||||||l I NW 1 I Filed July 6, 1931 firm Z k A VERCRUYSSEN AUTOMATIC DRAFT AND COMBUSTION CONTROL Feb. 6, 1934.

Patented Feb. 6, 1934 AUTOMATIC DRAFT AND CODIBUSTION CONTROL August Vercruyssen, Chicago, 111. Application July 6, 1931. Serial No. 548,899

12 Claims.

The present invention relates to an automatic draft and combustion control, and more particularly to a novel system of safe, automatic and efficient control for boilers or furnaces whereby to effect a considerable saving in fuel consumption and labor, as well as to provide a perfectly safe system. The invention contemplates a system adapted to automatically bank the fire, or if the same becomes low, to automatically cause a draft in the base or ash pit of the boiler or furnace.

Among the objects of the present invention is to provide a novel system of automatic draft and combustion control which is adapted to automatically bank the fire, or to cause a force draft is in the base or ash pit of the boiler or furnace whereby to provide an efficient control system.

A further object is to provide a system of draft and'combustion control whereby the coke, coal or other combustible material is more completely consumed than in systems now in use.

A still further object of the invention is the provision of a novel system of mercury switches adapted to automatically control the draft whereby to maintain the combustion as desired and required.

Another object is the provision of a novel system of draft and combustion control which is provided with a blower or fan for causing positive forced draft whereby to build up and maintain the desired combustion in the boiler or furnace.

Yet another object is the provision of a novel electrical circuit whereby to automatically regulate and control the combustion in the boiler or furnace by means of the pressure in the steam line.

A further object is the provision of an automatic draft and combustion control in which is provided a blower or fan connected into the ash pit of the boiler or furnace.

Another object is the provision of a blower or fan construction with a pivoted closure adapted to close by gravity when the fan is not operating, and to open by reason of the slightest suction whe the fan is operating to suck air through this closure and exhaust it into the base or ash pit of the boiler or furnace.

A still further object of the invention is the provision of a novel construction of check draft. The invention contemplates providing the check draft with pivoted closures or shutters connected to the damper chain, and then to the steam diaphragm regulator. These shutters or closures are of light construction and so pivoted and balanced as to operate at any desired pressure, regardless of how low the same may be.

Further objects are to provide a construction of maximum simplicity, efficiency, economy and ease of assembly, operation and control, and such further objects, advantages, and capabilities as will later more fully appear, and are inherently pos- 6 sessed thereby.

The invention further resides in the combination, construction and arrangements of parts i1- lustrated in the accompanying drawings, and while there is shown but one preferred embodiment, it is to be understood that the same is susceptible of modification and change,.and'comprehends other details and constructions, without departing from the spirit of the invention.

In the drawings:

Fig. 1 is a view in perspective of a boiler or furnace construction provided with my novel system of automatic draft and combustion controL.

Fig. 2 is a diagrammatic view of the electrical circuit of the system.

Fig. 3 is a fragmentary view with a portion in vertical cross section of the blower or fan construction.

Fig. 4 is a view in front elevation of the blower or fan.

Fig. 5 is a view in perspective of the pivoted closures or shutters forming the check draft.

Referring more particularly to the disclosure in the drawings, the boiler or furnace is designated generally as 1 and is provided with an exhaust or smoke pipe 2 provided with the usual damper. 3, and a check draft 4. The numeral 5 refers to the steam line which is directly connected to mercury switches 6 and 7, the former by means of a pipe 8, and the latter by means of a pipe 9. From this steam line passes the usual return flow or water pipe 10 provided with a steam gauge 11, thermometer 12, and valves 13.

The niercury switches 6 and 7 as shown in Fig.

2 are connected in the circuit of a power line and in series with a motor 14 operating a fan 15. As disclosed, the mercury switch 6 is connected in the power line and through a knife switch 16, through the wires 17, thence through the mercury tube 18 and wire 19 to the motor 14. The switch 0 7 is connected to the wires 20, then through the mercury tube 21 and wire 22 to the opposite terminal of the motor 14. As'disclosed, the switches are mounted in series with the motor. When it is desired, the current may be shunted around the mercury switch 6 by means of a lead 23 and hand switch 24 so that the circuit tothe fan may be manually closed by means of the switch 24 when the pressure in the steam line 8 is so low as to fail to trip the mercury switch and close the circuit to no the motor. As the pressure in the steam line is boosted or increased, the mercury switch 6 will close and the manually controlled switch 24 will be manually opened. This switch 6 will remain closed until the fire and steam pressure produced thereby is so low that the pressure can no longer be raised or increased without attention to the fire box, as by placing more fuel thereon. This novel control is to prevent the fan from continuing, and the small amount of fuel remaining in the fire box from being entirely consumed.

The mercury switch 7 is always closed except when the pressure increases above the maximum desired. When this switch 7 opens, it opens the circuit to the motor and of course the blower or fan is automatically stopped. As the steam pres sure decreases to normal or below a predetermined maximum this switch 7 again closes. Normally such a mercury switch is provided with an adjustable screw arrangement so as to adjust to the desired or predetermined pressure at which the switch will be thrown to open or closed position.

As disclosed in Fig. l the wires leading from the junction box 25 and hand switch 24 are shown as enclosed or encased in conduits 27 and 28. Likewise the power line leads from a primary source of current supply to the switch 16 in the junction box 25 are encased or enclosed in conduit 29.

Referring more particularly to Fig. 3, the blower or fan 15 comprises a rotating member 30 provided with vanes or blades 31, the member 30 being mounted upon the shaft 32 of the motor 14. When the fan is operating, the blades will draw air through the inlet or intake 33 and exhaust the same through a pipe or outlet 34 into the base or ash pit of the boiler or furnace. The intake port 33 is adapted to be closed when the fan is not operated by means of a closure 35 which is pivotally arranged and so balanced that the same will close by gravity when the fan is not operated, but as soon as the fan is rotating, a slight suction of air through the port 33 will tilt the closure and permit a direct passage of air therethrough. In order to prevent such a pivoted closure from spinning, the upper portion of the intake port or inlet 33 is provided with an arcuate portion 36 which is permanently arranged therein. This portion prevents the air from being drawn into the intake port and passing the same above and below the closure, which would cause the same to spin and provide a resistance to the direct passage of air therethrough. This closure may be made of any light material such as fibre or the like, and is so balanced and arranged that it will open at a very slight pressure. Connected to the steam regulator 37 is a pivoted lever arm 37 which is fulcrumed at 38, and connected to the extremity of one end of this lever arm is a damper chain 39 connected to the damper, and a chain 40 connected to the check draft 4.

Mounted in the check draft are provided a plurality of shutters or closures 41 which are pivotally mounted intermediate their width on rods 42 which are provided with outer extremities 43 to which is attached an arm 44 connected to the chain 40. This operating arm 44 will check the draft shutters or closures at a very low steam pressure which would move the lever arm 37 but a slight extent. The check draft closures or shutters are of very light materialand so balanced that they can be readily opened or closed at a predetermined pressure. The movement of this arm 37 may likewise be varied by means of a weight 45 which is slidably arcombustible material in the boiler or furnace -sure cannot be raised. When there is sufficient ranged therein. The check draft 4 and damper 3 are so arranged and positioned that when one is open the other is closed, it being understood that the damper 3 is never closed to the full extent so as to permit the escape of the exhaust gases at all times.

From the above description and disclosure, it will be readily seen that I have provided an efiicient, safe and automatic draft or combustion control whereby the fire may be banked or the intensity increased as desired. By reason of the system and arrangement of the electrical circuit and the mercury switches therein, there is no danger of a complete consumption of the when the fan is operating for the reason that the mercury switch 6 will cut out this blower or fan or open the circuit thereto when the fire in the combustion chamber is so low that the presheat or the steam pressure is raised above normal or a predetermined amount, the mercury switch 7 will automatically shut off the blower or fan, or open the circuit thereto, thus affording a positive and efficient control system.

In starting the fire, as for example when the same is so low that the pressure cannot build up, or there is no fire in the fire box the operator starts the fire, adds fuel thereto, and closes the hand switch 24 so as to shunt the current around the switch 6 and close the circuit to the motor for operating the fan, it being understood that the mercury switch '7 remains closed at all pressures below predetermined maximum. As the pressure increases, the mercury switch 6 will automatically close and the operator can then manually open the switch 24, the switch 6 remaining closed as long as there is suflicient pressure. As the pressure increases to above a predetermined maximum, the mercury switch 7. automatically opens, thus breaking the circuit to the fan so as to stop operation thereof. The knife switch 16 in the junction box25 is adapted to openthe circuit whenever it is so desired.

By this construction, it is possible to secure more complete combustion, and the fire is automatically banked as the pressure decreases and the circuit to the fan is opened.

Having thus disclosed the invention,

I claim:

' 1. A system of draft and combustion control for boilers or the like, comprising a blower, a pair of normally closed switches connected to the steam line from the boiler and adapted to open an electrical circuit to the blower, one of said 30 switches opening the circuit when the pressure in the steam line decreases below a predetermined minimum, and the other opening said circuit when the pressure in the steam line increases above a predetermined maximum where- 135 by the draft is automatically regulated.

2. A system of draft and combustion control for boilers or the like, comprising a blower, a pair of switches connected to the steam line from the boiler and adapted to open an electrical circuit to the blower, one of said switches being constructed and arranged to open the circuit when the pressure in the steam line decreases below a predetermined minimum, and the other switch being constructed and arranged to open 145 said circuit when the pressure in the steam line increases above a predetermined maximum and again closes said circuit whereby to again start the blower when the pressure decreases below the predetermined maximum.

3. A system of draft and combustion control for boilers or the like, comprising a blower, a

pair of automatically operated switches one of said switches being constructed and arranged to stop the blower when the pressure in the steam line of the boiler decreases below a predetermined minimum, the other switch being constructed and arranged to stop the blower when the pressure increases above a predetermined maximum, the last mentioned switch being constructed and arranged to again start the blower when the steam pressure decreases below the predetermined maximum.

4. A system of draft and combustion control for boilers and the like, comprising a blower, automatically operated switch mechanism including a switch constructedand arranged to stop the blower when the pressure in the steam line of the boiler decreases below a predetermined minimum, and another switch constructed and arranged to stop the blower when the pressure in the steam line increases above a predetermined maximum, and automatic closure means for said blower adapted to close the inlet to the blower whenever the blower is not operating.

5. A system of draft and combustion control for boilers and the like comprising a blower, automatically operated switch mechanism including a switch contructed and arranged to stop the blower when the pressure in the steam line of the boiler decreases below a predetermined minimum, and another switch constructed and arranged to stop the blower when the pressure in the steam line increases above a predetermined maximum, and a balanced closure adapted to be automatically opened by the suction of the blower and automatically closed when the blower is not operating. 1

6. A system of draft and combustion control for boilers and the like, comprising a forced draft mechanism, means operable by the steam pressure for stopping said mechanism when the steam pressure decreases below or increases above predetermined amounts, and pivoted plates responsive to the steam pressure forming a check draft, said plates being pivoted intermediate their length and so balanced that a slight pressure will operate the same, whereby to open or close the check draft dependent upon the steam pressure generated.

'7. A system of draft and combustion control for boilers or the like comprising a motoroperated blower and a circuit controlling the blower, said circuit including two normally closed pressure operated. switches, one of said switches being so constructed and arranged as to open the circuit in response to increase in pressure above a predetermined maximum, and the other switch being so. constructed and arranged as to open said circuit in response to a drop in pressure below a predetermined minimum.

8. A system of draft and combustion control for boilers or the like comprisinga forced draft mechanism, means for normally operating said forced draft mechanism, means responsive to an excess of steam pressure generated by the boiler above a predetermined maximum for stopping said forced draft mechanism, and other means responsive to a drop in steam pressure below a predetermined minimum for also stopping said forced draft mechanism.

9. A system of draft and combustion control for boilers or the like comprising a blower, a motor therefor, means for normally actuating said motor, means operable by steam pressure generated in the boiler constructed and arranged to stop said actuating means when the steam pressure exceeds a predetermined maximum, and other means controlled by the steam pressure in the boiler and constructed and arranged to stop said actuating means when the pressure drops below a predetermined minimum.

10. A system of draft and combustion control for boilers or the like comprising a motoroperated blower, a circuit controlling the blower, said circuit including two normally closed pressure operated switches operable by the steam pressure generated in the boiler, one of said switches being constructed and arranged to open the circuit in response to an increase in pressure above a predetermined maximum, and the other switch being constructed and arranged to open said circuit in response to a drop in pressure below a predetermined minimum.

11. A system of draft and combustion control for boilers or the like comprising a blower, means for. normally operating the blower, means responsive to an excess of steam pressure generated in the boiler above a predetermined maximum for stopping said blower, other means responsive to a drop in steam pressure below a predetermined minimum for also stopping said blower, and means whereby said stopping means are normally subjected to the steam pressure of the boiler to be controlled.

12. A system of draft and combustion control for boilers and the like, comprising a blower, means for operating the blower, means constructed and arranged to stop the blower when the pressure in the steam line of the boiler decreases below a predetermined minimum, and other means constructed and arranged to stop the blower when the pressure in the' steam line of the boiler increases above a predetermined 

